Biomimetic cell in-situ self-healing PCL/CNT conductive composites for flexible pressure sensors with high sensitivity and wide linear measurement range

Flexible pressure sensors are widely used in wearable electronic devices, human motion detection, and electronic skin. Conductive composites are the core component of flexible pressure sensors. However, they suffer from mechanical damage during long-term cycling, which degrades sensor performance. This study proposed a biomimetic cell in-situ self-healing polycaprolactone/carbon nanotube composite (BCISPC). The core-shell structure of BCISPC endows the composite with a low percolation threshold (0.012 vol%), high electrical conductivity (13.3 S/m), and fast electrothermal self-healing capability (18 s). The efficient in-situ self-healing ability of the composite preserves its surface microstructure during self-healing. In addition, a self-healing hierarchical microstructured flexible pressure sensor was prepared using BCISPC. The sensor has a high sensitivity (159.4 kPa$^{-1}$), wide linear measurement range (0–500 kPa), fast response time (34 ms), and good cycling durability (1000 cycles). Given its high performance, this sensor has various applications in wearable electronics, medical monitoring, and human-machine interfaces.